A conventional blind rivet comprises a rivet body and a mandrel extending through the rivet body, and is set by inserting the rivet body in a work piece, applying a tool to the blind rivet to engage the mandrel and a head of the rivet body and then causing the tool to withdraw the mandrel while restraining the rivet body by the engagement with the head, thus to cause deformation of the rivet body to set the rivet.
The force required to set a rivet, and the distance which the mandrel needs to be pulled to set the rivet--varies from one rivet to another. High strength rivets require high setting loads and can normally be set with a comparatively short stroke: longer, smaller diameter rivets or rivets adapted to split upon setting require a longer stroke but can normally be set with a lower setting load.
It is often the case that a user of rivets will wish to change from using one type of rivet to another, and if the change is one which requires a change from a shorter, more powerful stroke to a longer, less powerful stroke, the user will need to use a second tool.
An alternative, which is generally regarded as bad practice, is to use a shorter stroke tool to perform two pulling operations to set the rivet, which as well as tending to give unreliable setting of the rivet is time consuming.
Rivet setting tools are comparatively expensive, and it would be advantageous to be able to adapt a rivet setting tool to perform either a shorter more powerful stroke or a longer, less powerful stroke.
It is one of the objects of the present invention to provide a blind rivet setting tool which is convertible between operation with a shorter, more powerful, stroke and a longer, less powerful, stroke.